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Capella_Ben
09-06-2018, 05:20 PM
Hi All,

Here is my Prawn Nebula.

https://www.astrobin.com/350292/?nc=user


If you have any ideas on how it can be improved, I'd love to hear.

Thanks

Ben
..

LewisM
09-06-2018, 05:36 PM
Number one: it's black clipped, and quite harshly. Using your PNG on astrobin, I managed to extract the image below, but I could likely get more if it was not black clipped. (resampled at LOW res, hence the poor quality)

Secondly, green is...well...yak for DSO's - most astrophotographers go out of their way to remove green from images (there are green removing scripts for photoshop and PixInsight). You'd be better served converting it to the Hubble Palette.

Capella_Ben
09-06-2018, 06:18 PM
Thanks.

I have been mapping Ha to Green as to what I thought was the Hubble palette. I have also been turning it way down so that it does not overwhelm the image.

What is your interpretation of the Hubble palette?

Have been looking at other colour mapping to Ha, SII and OIII. Colour is very subjective (it seems) and comes down to taste.

I could bring the blacks up a bit, but it does show a bit too much noise and tends to detract from the image. I did go on the assumption that space is black... :)

Capella_Ben
09-06-2018, 06:45 PM
Oh and have you calibrated your monitor? Normally by default they are way out.

Capella_Ben
09-06-2018, 07:23 PM
I have re-stacked, and re-processed with less black clipping and with a different version of the Hubble palette.

Thoughts?

I don't see as much definition as the other version and it looks too washed out to me.

Slawomir
09-06-2018, 07:44 PM
The second version looks much better :thumbsup:

I usually boost a fair bit the OIII and SII signal when combining the channels into an RGB image.

More integration would help to show more structures and colours too. I had to combine nearly 20hrs of data to get a satisfying (to me) result for this DSO :)

Andy01
09-06-2018, 07:48 PM
Hi Ben,
First of all well done on this image, your stars are round, composition is pleasing and the data is solid.
As to Color palatte, well there’s two schools of thought, but both agree that one should try to represent all three wavelengths in visibly different hues.
Ha tends to be rich and as you have noted, can easily overwhelm the image.
Should you choose to render it in the ‘natural’ M&T green driven style then you’re nearly there, just dial back the ha luminosity a tad and watch the histogram so the the toe doesnt sit on the far left, leave some space and as Lewis rightly mentioned earlier, the subtle shadow details will show up well.
Or, as those in my ‘artistic ‘ camp prefer, use selective colour to basically eliminate green altogether and render it orange.
O3 to blue & S2 to red, (which then appears yellow).
Nb colour however is a highly subjective, ‘Dealers choice’ opportunity to show the three wavelengths in whatever colours you like, as long as you can see all three and that they are pleasingly balanced to the eye.
Fwiw here is my version-

https://www.astrobin.com/166688

A bit different to yours but that’s the way we roll in NB!
Google or search up that target on Astrobin and see what others have done, and make your colour selections based on whatever rows your boat!

Good Stuff, well done and keep going :thumbsup:

Capella_Ben
09-06-2018, 08:03 PM
Thanks Guys. I'll keep working on it.

I agree more integration time is required. Once I finish a mosaic experiment, I'll switch to doing more like 3+ hours per channel for a subject.

I'm still not sure what palette I should go with.

I think I see what you mean by using 'Selective Colour' in Photo Shop to get rid of the green (see attached)

multiweb
09-06-2018, 08:53 PM
Some very good details in that shot. Top shelf. Well done. :thumbsup:

RickS
11-06-2018, 08:24 AM
Hi Ben,

Here's a tutorial on getting the popular "gold & turquoise" look from Hubble Palette in Photoshop: http://bf-astro.com/hubblep.htm

Even if you don't like or want that look you might find it of interest.

Cheers,
Rick.